scholarly journals Effects of Geofoam Panels on Static Behavior of Cantilever Retaining Wall

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Navid Hasanpouri Notash ◽  
Rouzbeh Dabiri

Geofoam is one of the geosynthetic products that can be used in geotechnical applications. According to researches, expanded polystyrene (EPS) geofoam placed directly against a rigid retaining wall has been proposed as a strategy to reduce static loads on the wall. This study employed a finite difference analysis using a 2-D FLAC computer program by considering yielding and nonyielding states for retaining walls to explore the effectiveness of geofoam panels in improving the static performance of cantilever retaining walls. Retaining walls at heights of 3, 6, and 9 meters and geofoam panels with densities of 15, 20, and 25 (kg/m3) at three relative thicknesses of t/H = 0.05, 0.2, and 0.4 were modelled in this numerical study. In addition, the performance of the double EPS buffer system, which involves two vertical geofoam panels, in retaining walls’ stability with four panel spacing (50, 100, 150, and 200 cm) was also evaluated in this research. The results showed that use of EPS15 with density equal to 15 (kg/m3) which has the lowest density among other geofoam panels has a significant role in reduction of lateral stresses, although the performance of geofoam in nonyielding retaining walls is better than yielding retaining walls.

2009 ◽  
Vol 46 (3) ◽  
pp. 318-338 ◽  
Author(s):  
Saman Zarnani ◽  
Richard J. Bathurst

Expanded polystyrene (EPS) geofoam seismic buffers can be used to reduce earthquake-induced loads acting on rigid retaining wall structures. A numerical study was carried out to investigate the influence of wall height; EPS geofoam type, thickness, and stiffness; and excitation record on seismic buffer performance. The numerical simulations were carried out using a verified FLAC code. The influence of parameter values was examined by computing the maximum forces on the walls, the buffer compressive strains, and the relative efficiency of the buffer system. In general, the closer the predominant frequency of excitation to the fundamental frequency of the wall model, the greater the seismic loads and buffer compression. The choice of earthquake record is shown to affect the magnitude of maximum earth force and isolation efficiency. However, when the wall response for walls 3 to 9 m in height are presented in this study in terms of isolation efficiency, the data from scaled accelerograms and matching harmonic records with the same predominant frequency fall within a relatively narrow band when plotted against relative buffer thickness. For the range of parameters investigated, a buffer stiffness value less than 50 MN/m3 was judged to be the practical range for the design of these systems.


2021 ◽  
Vol 13 (9) ◽  
pp. 4754
Author(s):  
Muhammad Imran Khan ◽  
Mohamed A. Meguid

Expanded polystyrene (EPS) geofoam is a lightweight compressible material that has been widely used in various civil engineering projects. One interesting application of EPS in geotechnical engineering is to reduce the lateral earth pressure on rigid non-yielding retaining walls. The compressible nature of the EPS geofoam allows for the shear strength of the backfill soil to be mobilized, which leads to a reduction in lateral earth pressure acting on the wall. In this study, a finite element model is developed and used to investigate the role of geofoam inclusion between a rigid retaining wall and the backfill material on the earth pressure transferred to the wall structure. The developed model was first calibrated using experimental data. Then, a parametric study was conducted to investigate the effect of EPS geofoam density, relative thickness with respect to the wall height, and the frictional angle of backfill soil on the effectiveness of this technique in reducing lateral earth pressure. Results showed that low-density EPS geofoam inclusion provides the best performance, particularly when coupled with backfill of low friction angle. The proposed modeling approach has shown to be efficient in solving this class of problems and can be used to model similar soil-geofoam-structure interaction problems.


2011 ◽  
Vol 243-249 ◽  
pp. 959-962
Author(s):  
De Ling Wang ◽  
Li Guo

In this paper, the force against rigid retaining walls from backfill soil under static loads and vibration loads is analyzed within three cases. The first case is an ordinary retaining wall without expanded polystyrene (EPS) geofoam buffer. In the second and the third case, a layer of vertical EPS buffer with different density and elastic modulus is placed between a rigid retaining wall and backfill soil. Numerical simulation results show that the force against the same retaining wall in the treated cases is less than that in the untreated case, under both static loads and vibration loads. Moreover, the compression of different EPS buffer is studied. Under vibration excitation, when the density and elastic modulus of EPS buffer decreases, its compression increases and more wall force is mitigated. Simulation results accord with the physical shaking table test data. Numerical results and physical test demonstrate that EPS geofoam seismic buffers hold great promise to reduce loads against rigid retaining wall structures, especially earthquake-induced dynamic loads.


2021 ◽  
Vol 1197 (1) ◽  
pp. 012030
Author(s):  
Jayesh Harode ◽  
Kuldeep Dabhekar ◽  
P.Y. Pawade ◽  
Isha Khedikar

Abstract It is now becoming very essential to analyse the behaviour of retaining structures due to their wide infrastructural applications. The important factors which are affecting the stability of the retaining wall are the distribution of earth pressure on the wall, material of backfill & its reaction against earth pressure. There are several types of retaining walls, out of them the cantilever retaining wall is adopted for present design and study. In this paper, the study of literature based on the design of the cantilever retaining walls under seismic or dynamic conditions is studied. From the studied literature, many authors performed their calculations in Excel sheets by a manual method. Then the Results obtained from the manual calculation are then validated in STAAD pro. Several authors show the calculated quantity of steel and concrete required for various heights of walls. It is also concluded from the study that the design of cantilever retaining wall is suitable, safe, and economical up to a height of 6m, after that banding moment at toe increases. Some authors have also shown the calculated factor of safety for different height conditions. From the study of mentioned literature, we can recommended to also show the graph of bending moment with height variation. Both the designs are done for various heights ranging from 3 m to 6 m.


CANTILEVER ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 15-24
Author(s):  
Syahril Alzahri ◽  
Adiguna ◽  
Bimo Brata Adhitya ◽  
Yulindasari Sutejo ◽  
Reffanda Kurniawan Rustam

A typical relatively steep slope makes the Lb. Selasih – Bts. Kota Padang KM.29+650 experienced a landslide in 2017. So, it is necessary to strengthen the slope to overcome the landslide. Alternative slope reinforcement used is reinforcement using cantilever retaining walls or geotextiles. Slope stability analysis before and after were analyzed using the Slope/W program. The output produced by Slope/W program is the value of the safety factor. The safety factor value for the state of the original slope is 1.100. It shows that the slope in the original condition is unstable and vulnerable to landslide hazards. The retaining wall has a height of 11 m and a base plate width of 8 m. The results of the analysis showed that the cantilever retaining wall securely with stands shear, rolling, and bearing capacity of the subgrade with a safety factor value of 1.620; 1.550; 2.160, while geotextile reinforcement has a height of 16 m and an ultimate tensile strength of 200 kN / m. The results of the analysis showed that the reinforcement of the geotextile safely sliding, stability, and bearing capacity of the subgrade with a safety factor value of 1.600; 2.330; 2.860. Both of these reinforcements are safe to stabilize the slope by increasing the value of the slope safety factor by 2.235 for strengthening the cantilevered retaining wall and 2.279 for strengthening the geotextile.


2020 ◽  
Vol 14 (1) ◽  
pp. 6
Author(s):  
Jefrizal Sihombing ◽  
Yoga Satria I ◽  
Amelia Rosana Putri ◽  
Widya Utama

The modeling of retaining wall is adapted to the real conditions on Balerejo Kalegen Street. This wall modeling uses a Cantilever type wall which has a height of 550 cm and a width of 385 cm which is useful for calculating the minimum strength of a cantilever wall for retaining the soil on the Balerejo Kalegen road. In addition, this wall is modeled to have a width of 55 cm, a heel width of 130 cm, a foot width of 130 cm, the width of the next leg is 100 cm, with a wall that enters it is 50 cm and using evenly distributed load variations has been adjusted where the load used is the burden amounting to 11,138, 5.5, 0.3869 tons. When inputting data into SAP 2000 beforehand, calculations must be made related to the force that will affect the wall, then modeling the walls according to the Cantilever shape. After that, Cantilever wall that has been made can be calculated compressive strength and shear strength where the compressive strength of the front wall with an average of 175,154 tons m, the back with an average of 62,666 tons m, the average front heel 866,054 tons m , and the back heel averages 910,463 tons m. Keywords: Cantilever, Retaining Walls, SAP 2000.


Author(s):  
Mohsen Kalateh-Ahani ◽  
Arman Sarani

Modern buildings should provide some degree of safety against severe earthquakes. However, it is not economically feasible to construct buildings that withstand extreme loads without avoiding damage. In performance-based design, structural engineers and owners work together to achieve the best possible balance between construction cost and seismic performance. In this study, by employing a metaheuristic optimization, we have tried to extend the concept of performance-based design to retaining wall structures. According to the AASHTO LRFD Bridge Design Specifications, permanent displacement of retaining structures are tolerable, as long as the movement does not lead to unacceptable damage to the structure or facilities located in or near the moving earth. The decision on performance expectations needs to be made by owners with structural engineers providing a realistic assessment of the cost of designing to avoid the movement. To make this assessment possible, we developed a multi-objective optimization framework for simultaneous minimization of the construction cost and the permanent displacement of cantilever retaining walls. The effectiveness of the proposed framework was evaluated in the design of a typical cantilever retaining wall of 8 meters in height, once with both a toe and heel slab and once with either of them. The results indicated that obtaining the Pareto front of optimal solutions for these objectives, provides useful information that helps owners to select a solution that is the most economical in a trade-off between the construction cost and performance expectation.


1996 ◽  
Vol 33 (2) ◽  
pp. 290-308 ◽  
Author(s):  
Hans H Vaziri

A practical numerical model is described for analysis of flexible retaining walls. In terms of capabilities, the model fits between traditional limit equilibrium methods and full finite element approaches; it overcomes many of the limitations associated with the former but is not equipped with the versatility offered by the latter. Using an approach similar to that adopted in boundary-element based models, the wall stiffness is represented by a series of elastic beam elements whose stiffness is combined with that of the prestressed struts and the soil to form, the overall stiffness matrix. The stiffness matrix of the soil is obtained by inversion of flexibility matrices generated by interpolation and sealing of flexibility matrices calculated for a simplified soil model using finite element methods. The soil behaves linearly elastically, as long as the pressures correspond to stress levels lying between the limits. Where the lateral displacement of the wall corresponds to a pressure outside of these allowable limits, correction forces are added until the resulting pressures are within the active or passive pressures. Arching is permitted by considering the forces acting on the wall compared with the forces consistent with possible failure surfaces within the soil. Other features that can be accomodated by the model include struts, variations in water table, and the effects of surcharges. The proposed model has been shown to capture the displacement, anchor loads, and lateral stresses for several field problems. Based on these studies and other field applications of the model a number of points have been observed that are of practical interest; these points are separately listed. Key words: numerical analysis, retaining wall, anchor, arching, soil–structure interaction, deflection.


2020 ◽  
Vol 11 (2) ◽  
pp. 39 ◽  
Author(s):  
Esra Uray ◽  
Serdar Çarbaş ◽  
İbrahim Hakkı Erkan ◽  
Murat Olgun

In this paper, the investigation of the optimum designs for two types of concrete cantilever retaining walls was performed utilizing the artificial bee colony algorithm. Stability conditions like safety factors sliding, overturning and bearing capacity and some geometric instances due to inherent of the wall were considered as the design constraints. The effect of the existence of the key in wall design on the objective function was probed for changeable properties of foundation and backfill soils. In optimization analysis, wall concrete weight which directly affect parameters such as carbon dioxide emission and the cost was considered as the objective function and analyzes were performed according to different discrete design variables. The optimum concrete cantilever retaining wall designs satisfying constraints of stability conditions and geometric instances were obtained for different soil cases. Optimum designs of concrete cantilever retaining wall with the key were attained in some soil cases which were not found the feasible optimum solution of the concrete cantilever retaining wall. Results illustrate that the artificial bee colony algorithm was a favorable metaheuristic optimization method to gain optimum designs of concrete cantilever retaining wall.


Author(s):  
Ali Kaveh ◽  
Kiarash Biabani Hamedani ◽  
Taha Bakhshpoori

In this paper, optimum design of reinforced concrete cantilever retaining walls is performed under static and dynamic loading conditions utilizing eleven population-based meta-heuristic algorithms. These algorithms consist of Artificial Bee Colony algorithm, Big Bang-Big Crunch algorithm, Teaching-Learning-Based Optimization algorithm, Imperialist Competitive Algorithm, Cuckoo Search algorithm, Charged System Search algorithm, Ray Optimization algorithm, Tug of War Optimization algorithm, Water Evaporation Optimization algorithm, Vibrating Particles System algorithm, and Cyclical Parthenogenesis Algorithm. Two well-known methods consisting of the Rankine and Coulomb methods are used to determine lateral earth pressures acting on cantilever retaining wall under static loading condition. In addition, Mononobe-Okabe method is employed for dynamic loading condition. The design is based on ACI 318-05 and the goal of optimization is to minimize the cost function of the cantilever retaining wall. The performance of the utilized algorithms is investigated through an optimization example of cantilever retaining wall. In addition, convergence histories of the algorithms are provided for better understanding of their performance.


Sign in / Sign up

Export Citation Format

Share Document